1. Field of the Invention
The present invention relates to an operation program editing device configured to edit an operation program for a programmable controller, the operation program being described to include a plurality of steps each indicative of an individual control process and a transition indicative of a transition condition between the plurality of steps, and a method for the operation program editing device to edit the operation program.
2. Description of Related Art
Conventionally, as a programming language for a programmable controller that controls a facility such as a machine tool, a ladder logic (a ladder language), a sequential function chart (a SFC language), a function block diagram (a FBD language), and the like have been known, as prescribed in the IEC61131-3 standard. Among them, the SFC language is a format that describes a flow of an individual control process like a flowchart. Since the SFC language has high clarity, the SFC language has been widely used in recent years.
In the meantime, a program described by the SFC language is described on the presumption that a plurality of steps each indicative of an individual control process is executed sequentially from the top. Accordingly, in a case where execution of the program described by the SFC language stops halfway due to some troubles while a programmable controller is executing the program described by the SFC language, it is difficult to restart a control process of a step subsequent to a step at which the troubles occur, at the time of reactivation after troubleshooting.
In view of such problems, the applicant of the present application has proposed a programmable controller that can appropriately reactivate a program described by the SFC language after the program stops halfway (see Japanese Patent Application Publication No. 2008-97079 (JP 2008-97079 A)).
However, the programmable controller described in JP 2008-97079 A assigns a ladder program described by the ladder language to each transition indicative of a transition condition between steps, and the ladder program is constituted by combining a halfway activation flag that is turned on when the ladder program is reactivated, an activation condition of a step just before each transition, and the like. Therefore, it takes time for a programming operation of the ladder program. Further, a content of such an operation program is not shown in the SFC language expressed like a flowchart, so there is also a problem that a third person (e.g., a person in charge of facility maintenance) except an editor of the program is hard to understand the content. Thus, the programmable controller described in JP 2008-97079 A left room for improvement.